Cyclone.. Which one? ClearVue won

[Joe Mioux]

My concerns are the lack of power with the 2HP units. That is why the 5HP looks good to me.


I want to get this purchase right the first time as I am going to start asking questions in the laser woodworking forums and I will not have the money to buy another cyclone after that forum finishes with me

Getting all of the parts shipped from one source and having everything fit is important to me. I don't want to order from several sources, run all over the country to find this and that and have to cobble up stuff to get it to work.

Ed:

I have the Gorilla. If you have not yet spoken with the Oneida people call them with your requirements. They are the experts. If a 2hp unit is too small they will recommend the 3hp, etc.

More important to me than the DC was Oneida's customer service. Since I purchased their product, they did my duct work desin at no charge! I know that it is engineered properly.

I compared Oneida's prices to another well known duct work vendor and Oneida's price beat the other company.

As you stated you want you want all the parts to fit the first time and you don't want to be running all over the place finding parts to make your DC operate.

In other words, Oneida will provide you with a complete system. All you have to do is assemble. In addition, dealing with one source gives you the benefit of having that company keep a record of your purchases and the drawings of your shop in the database. So, in the future when you need to modify your system, they will have all the information needed for the modification

Joe

[Jim DeMarco]

Ed,

Just like to add my 2 cents here. Everyone has provided some very good info, and the topic of CFM was briefly touched upon. Also the last post directed you to contact Oneida, very good idea. A second source is air handling systems, they have a great section on designing your duct work.
The key to a great system is to spec out and purchase your dust system AFTER the duct work. First off pick your two primary machines, and spec out the size to maintain between 3500 to 4000 FPM velocity in the pipe. Next design the run the duct will take, the easiest calc is to convert everything to straight pipe equivilants....
The key is to maintain proper duct sizing to maintain the velocity through the losses.... shoot me an email and I can better explain.

The point to all of my ramblings is, design the system, do the math, and when you are finished you will know the proper duct size, and the pressure drop at the dust collecter. CFM ratings are vauge actually, the information you need is the CFM rating AT X inches of water (pressure drop).

There is a great section on airhanling systems website. I would be more than happy to crunch numbers for anyone out there. I hope this helps out...

Jim

[Steve Cox]

I have the 2hp Woodsucker and have found it to be an excellent unit. There used to be some info on the Bill Pentz site about why he had gone with a 5hp motor for his design and it was because of the impeller. If you were using a more efficient impeller i.e. "caged" or an "airfoil" then 2hp was all the power you needed. I'm not sure if that info has changed or not as once I figured out what unit I wanted I stopped doing extensive reading on the subject. I had had enough headaches trying to figure it all out!!!

[Ed Lang]

Thank you everyone.

I am going now to find the air flow required for each of my machines, make a drawing of the shop layout and then make a phone call or two.

[Bob Dodge]

Hi Ed Lang,

When deciding on which dc is most appropriate for your shop requirement, you have to look at only one branch of your planned network; the "worst-case scenario" branch. The specific volume (cfm) and static pressure resistance of that branch should be determined, then compared to the "system" performance curve of the dc's which are being considered.

Looking at cfm alone, can be quite misleading. You have to know at what static pressure that particular cfm rating occurs.

Is a 5 hp dc necessary? That depends on your shop requirement, and the individual system performance curve of that particular dc.

Many of the current crop of 2 hp cyclones, are using 7" intakes and 13.5" impellers. This allows for a high cfm rating, but at low static pressure. Remember, these dc's are tested with a very short length of pipe, usually about 10x inlet diameter. On a 7" intake, that's just under 6 ft(70") of 7" pipe.

Let's look at a typical rating of approximately 1200 cfm@ 2" sp. What exactly does that 2" sp mean? The 2" sp represents the total suction, or pressure difference, between the system, and atmospheric pressure.

That "total static pressure", gives you two components. First, you get "velocity pressure". That's the air pressure generated by the speed of the airstream in a given pipe diameter. Second, you get the power to overcome the resistance of that pipe, or "static pressure loss". In other words, total static pressure, or suction, equals velocity pressure AND static pressure loss.

You need about 1" velocity pressure, to get a flow of 4000 fpm in a pipe. If you managed to get a total sp reading of only 2" sp with that short test pipe, that means you only have 1" of resistance power. As you add to that resistance, by lengthening your duct, you consume part of your velocity pressure. (CFM goes down). Once that velocity pressure drops below 1" wc, you have to start thinking about going with a smaller pipe diameter. Usually, that's the next size down, or 6" pipe.

The 6" pipe, will dramatically increase total static pressure. That means that both velocity pressure, and static pressure resistance will increase. You will now get a lower cfm reading, but at a much higher suction level. Now, you can play with duct length, up to the point where velocity pressure drops below 1" wc. Remember, 1" velocity pressure, is about 4000 fpm.

Now "IF" your dc could still pull 1200 cfm in a 6" pipe, then your total SP reading might be 1200cfm at 4.85"sp. That's just an example. It won't happen. Why? Because that particular dc was only capable of pulling that 1200 cfm "AT" 2" sp. It will now pull less cfm, but at a rating higher than 2" sp. You'd typically have to add about 1.3"(bell-mouth)-2.1" sp(plain end pipe) to account for the new "entry loss" of the 6" pipe. You'd now be operating at 3.3"sp- 4.1"sp.(depending on inlet type) Once you've added that new entry-loss, you only have to deal with "length resistance", which is .045" per foot (at 4000fpm, smooth-walled pipe)

If you look at your dc's system performance curve once again, look at that particular sp point on the curve, to see how many cfm you'll get. Remember, that's only the short test pipe, with a 6" reducer on it. You've not added any ducting yet.

Here's an example. Look at the system performance curve for the 2hp Commercial Oneida in this test result chart. At 3.3"SP(bell-mouth), it's pulling roughly 1100 cfm. At 4.1"sp (plain-end pipe) it's pulling about 1030 cfm.

That should allow you to add another 2.9" sp resistance to your ducting, before you start dropping below 4000 fpm in the 6" pipe. (785 cfm at 6.2"sp according to curve)

If you're going to use a 7" main, you have to keep an eye on that 1100 cfm flow rate. You don't want that to drop much below 950 cfm, for a velocity of 3500 fpm in that 7" pipe. You'd only have about 1.5" sp to play with, if that were the case.

The figures I've used to calculate entry loss, are for a bell-mouth entry. That simulates a properly tapered hood. Using a properly tapered hood will reduce that "entry loss" resistance, and therefore, buy you more cfm. Had I used a plain-end pipe for calculation, I'd lose another .8" sp roughly (less cfm). To calculate the new entry loss, you use only the difference between the old entry loss, and the new entry loss.

Keep in mind, this particular version of the 2 hp Oneida Commercial had a 14" impeller. Current versions ship with a 13.5" impeller I believe.

Bottom line, a dc such as this Oneida should easily handle 95% of small-shops. If you're contemplating a 1200 cfm requirement at a particular source (37" dual-drum snader, etc), use 7" pipe, and keep it VERY short to that machine. With all the others requiring 800 cfm at source, you have a fair bit of reach. Roughly 35 feet of all 6" pipe, or a longer combination of 7" main, with 6" drops, not exceeding 1.5"sp in "length resistance".

There's also a fair amount of "grey area" with air flow. For example, you may ideally want to have 3500 fpm in a horizontal main to handle any kind of woodworking waste you throw at it, but if your farthest machine is producing wood-flour, you can get away with 2500 fpm in that main. Careful planning regarding shop-layout, will increase the "reach" of that dc.

If you're trying to fit a dc into an already layed-out shop, give some thought to where you want to place it. If by necessity that means an unusually long run of pipe, THEN you may have to consider a different dc. There are many ways to go. Perhaps a cyclone with a caged back-inclined impeller, like a Torit-Donaldson. That'll get you more static pressure at the same horsepower.($$$$$) Perhaps a well-designed single-stage.

Remember that those elbows add up REALLY quickly. A single elbow can consume 1/2"sp.(12 feet of pipe)

Bob

PS. The underscoring was unintentional, sorry.

[Jim Becker]

Bob, the original Oneida 2hp Commercial did have a slightly larger impeller, but it was not the same design as the current 13.5" which moves a lot of air, more than making up for the slight difference in the diameter. (I have one and it rocks) The Gorilla 2hp unit uses the same impeller. It's the end result that counts.

[Michael Perata]

I replaced a Jet DC 1100C with an Onieda 2HP Com'l unit and now the shop stays clean.

Maybe I could have saved some money elsewhere, but the Onieda unit works and that's what I wanted.

[Bob Dodge]

Hi Jim,

I just noticed Oneida's latest product description. I was wondering in what way the impeller is different. They appear to describe two different impellers now.

The one they refer to as a "back-inclined", is actually a back-curved radial, is it not? They also talk about an airfoil as well, so I'm a little confused.

I'm getting a bit of a chuckle out of the recently "increasing" performance on some of those dc's. The cfm ratings are higher than they were two months ago, but at reaaaaaally low static pressure points. 1400 cfm at 1" sp??????????

They'd have to take that measurement in an 11" pipe, to get that kind of reading. Too bad really. I find that only confuses people. If that 1400 cfm were flowing in a 1 foot long, 7" diameter pipe, you'd get a reading of 1400 cfm at 5.07"sp, yet their own curve shows about 1000 cfm at that pressure. Hmmmm. Gets curiouser and curiouser.

Mind you, I still think it's a heckuva dc, especially for that price. The Grizz, too. Now I'm wondering who's gonna come out with the "Godzilla". Which reminds me. Whatever happened to the Taco Bell Chihuahua? "Heeere leezard, leezard".

Bob

[Allan Johanson]

I'm getting a bit of a chuckle out of the recently "increasing" performance on some of those dc's. The cfm ratings are higher than they were two months ago, but at reaaaaaally low static pressure points. 1400 cfm at 1" sp??????????

They'd have to take that measurement in an 11" pipe, to get that kind of reading. Too bad really. I find that only confuses people. If that 1400 cfm were flowing in a 1 foot long, 7" diameter pipe, you'd get a reading of 1400 cfm at 5.07"sp, yet their own curve shows about 1000 cfm at that pressure. Hmmmm. Gets curiouser and curiouser.
Bob

Marketing departments everywhere are working overtime trying to sell DCs, that's why you keep seeing these useless numbers.

Check out Kraemer and see what numbers they're pushing. xxx cfm @ 1" SP. Completely useless. If you can't trust a big industrial name, who can you trust?

http://www.kraemertool.com/smportcyc.htm

Too much bunk out there.

For myself, I ignore all the max cfm claims. Useless to me. For a smaller DC I'd start looking at a system chart in the 5-6" SP range to get a better idea of what I'd see in my shop or in the 7-10" SP range for something like a Bill Pentz cyclone. That fan pulls like crazy.

But I do have a piece of advice for all you folks out there who live and die by DC calcs alone....all your math ain't worth a hill of beans when you actually hook up a machine to your carefully calculated theoretical airflow numbers.

After all, if all that mattered was getting xxx cfm at the end of a pipe before you hook up a machine, then hooking up a 6" pipe to a small palm sander would work well too. But that isn't the case. The machine itself plays a massive role in this.

In my shop I can have 1400cfm being delivered to a machine, but when you actually hook it up the final airflow drops down to anywhere from 780cfm to 1200cfm depending on the machine using the identical duct run. All kinds of factors kick in here.

Bottom line, don't fret too much about the math.

Cheers,

Allan

[Chris Lee]

Ed,

I have the Gorilla and all I can say is that I can not imagine needing much more suction. I have it set up with about 6 feet of 7" duct with a 6" drop and then about 10 feet of 6" flex hose that I drop down to 4" at the machine. I use it fior my planer, jointer, bandsaw and tablesaw mostly. It picks up just about everything.

Good Luck with your decision. I am not that far from you if you want to see how it runs sometime.

Chris

[Bob Dodge]

DC's like the Kraemers, use a completely different system from the consumer machines. Most industrial dc manufacturers use the same system. They are NOT showing you "AT WHAT" static pressure the dc is operating at, they are showing you the effect of adding "external static resistance".

Every Kraemer chart you look at, starts with the volume the dc is pulling, with 1" of static resistance added to the dc, then 2", then 3" etc. THAT'S why they all start at 1" sp. They're showing you what you'll get as you add ducting. 1", is NOT the operating point of the dc. That might be something like 800 cfm AT 3.7"sp for example, and with 1" sp added, your operating point will now be 4.7" sp.

With consumer dc's, you have to figure that out yourself. You have to take into consideration the inlet pipe for example, and calculate a new entry-loss if you're going to use smaller diameter drops. Then, from there, you have to calculate the effect of adding your pipe.

Bob

[Jim Becker]

I'm getting a bit of a chuckle out of the recently "increasing" performance on some of those dc's. The cfm ratings are higher than they were two months ago, but at reaaaaaally low static pressure points. 1400 cfm at 1" sp??????????

Bob, a fan curve only shows the performance of the system through a range of lab test conditions. But it does shows you what kind of airflow to expect in general from your situation at a given static pressure once your duct work and hoods are in play. In the case of Oneida, they appear to have adopted the max CFM figure from the fan curve in their marketing materials (surprising to me), probably to deal with competitive issues. But the curve is what is important when you compare systems...not the marketing materials. Getting a fan curve on many units is hard, unfortunately, especially one that is honest and accurate. I'm hoping the lessons learned in those systems are futher leveraged to provide better systems for the hobbiest shops, too.,

I think we are wandering down an unproductive path if we worry about how ridiculous a 1" SP figure is relative to real life (which it is) since the curves are just a resource to help you calculate where a given system will perform in your shop with duct work. They have to start and end the curve somewhere! It also points out the theoretical max air that the thing could push which might be useful when comparing fan types and sizes. It's also good to look at the max SP the system can handle before performance falls below what is required to service your tools and duct work...which brings up something else...

One thing that really is interesting is the advent "high suction" (SP) systems that Oneida has been releasing in the past couple of years. This is the result of greater use of CNC technology in small pro shops and the dust collection characteristics on smaller tools that necessarily have high SP requirements due to small ports, hoses, etc.

[Bob Dodge]

Hi Jim,

I wasn't referring to "fan" curves. I'm talking about "system" curves. About three or four months ago when those cyclones came out (Gorilla/Grizz), they both showed lower system performance ratings at the bottom end, and at already low static pressure. Then they both started showing higher cfm ratings, at even lower static pressure readings. Now, they're over 1400 cfm AT 1" sp. Like I said, you have to use 11" pipe to get a reading like that.

Here's the Beacon Engineering calculator. Try pulling 1400 cfm through a 7" pipe, and tell me what static pressure you get. Remember, total static, is the combined total of velocity pressure, and static pressure loss. That's a fan law. The calculator will give you both components, and you have to add those together.

If you're not familiar with this calculator, just under the top section where you enter pipe diameter, airflow(cfm), and pipe length, you'll see "Duct entry configuration". Choose "plain duct end". You can look at other like a bell-mouth entry for example, but for now, stick to "plain duct end".

Now scroll to the very bottom and select "Vertical discharge, no loss". Hit enter, and there's your total.

Hint: When entering "duct length", use 1 ft. This minimizes "length" loss. You just want to see what the operating point is at your dc's inlet. Alternatively, you could use "6ft", to simulate a test duct with 10x diameter. You'll get a slightly lower reading because of the 6 ft "length" resistance.

http://www.freecalc.com/ductfram.htm

Bob

[Jim Becker]

I wasn't referring to "fan" curves. I'm talking about "system" curves.

I believe we are just using different terms for the same thing. Like anything, the extremes at the low end of the SP axis are not important since they are not realistically acheivable. At the low end of the curve (higher SP), you need to know when the system/fan can no longer move enough air at enough velocity to work. One should be asking, "Can this system move x CFM at y SP and a given minimum velocity when my duct work and hoods calculate as..."

[Allan Johanson]

DC's like the Kraemers, use a completely different system from the consumer machines. Most industrial dc manufacturers use the same system. They are NOT showing you "AT WHAT" static pressure the dc is operating at, they are showing you the effect of adding "external static resistance".

Every Kraemer chart you look at, starts with the volume the dc is pulling, with 1" of static resistance added to the dc, then 2", then 3" etc. THAT'S why they all start at 1" sp. They're showing you what you'll get as you add ducting. 1", is NOT the operating point of the dc. That might be something like 800 cfm AT 3.7"sp for example, and with 1" sp added, your operating point will now be 4.7" sp.

With consumer dc's, you have to figure that out yourself. You have to take into consideration the inlet pipe for example, and calculate a new entry-loss if you're going to use smaller diameter drops. Then, from there, you have to calculate the effect of adding your pipe.

Bob

Hi Bob,

I know that you love DC topics and especially industrial stuff so I thought I'd correct you here. You are mistaken about Kraemer's info at the very least. What you wrote sounded very strange to me considering all the other info on Kraemer's site so I contacted them. Here is what they said about their 2HP cyclone:

************

Dear Allan,

Thank you for your e-mail regarding performance on our S 2-6 CYN dust collector.

The air flow for the fan is 1200 CFM at 1" S.P. The pressure drop over the filters is approximately 2". If the ducting has a static pressure drop of 6", the air flow will be 700 CFM.

The inlet to the fan is 7". You cannot hook up a bunch of 7" ducts to the system. A 7" duct would allow for (3) 4" duct connections or (2) 5" duct connections to allow for the proper drawing capacity.

I hope this information is helpful.

************

This makes sense with what I saw on their site. When you look up their performance system curve, you will see that at 8" SP it's flowing almost 700cfm, as in their example.

So the Kraemer chart I linked to is really a system curve just like what Oneida (and other companies) publishes.

FYI, on average this 2HP Kraemer cyclone performs a little better than the Oneida 2HP Commercial cyclone where it counts most (higher SP levels).

Cheers,

Allan